Transport software defined networking (SDN) may be considered to apply to application of SDN techniques to the transport layers of a service provider Wide Area Network (WAN). The transport layers include layer 0 and layer 1. In the seven-layer Open Systems Interconnection (OSI) model of computer networking, the physical layer is layer 1. The network cabling is sometimes referred to as “layer 0.” Layer 0 may use, for example, Dense Wavelength Division Multiplexing (DWDM) or photonics. Layer 1 may, for example, employ protocols such as Synchronous Optical Networking (SONET), Synchronous Digital Hierarchy (SDH) and Optical Transport Network (OTN).